DeepSpeed

8fa6b50b - Revert "BF16 optimizer: Clear lp grads after updating hp grads in hook" (#6508)

Revert "BF16 optimizer: Clear lp grads after updating hp grads in hook" (#6508) Reverts microsoft/DeepSpeed#5328 After offline discussion with @YangQun1 , we agreed that there is no memory effect as clear_lp_grads flag triggers zero_() ops which just zeros buffers and does not free any memory. the outcome is compute overhead.